A high definition multimedia interface (HDMI (registered trademark)) is a technique of a high definition digital video/audio interface, and this technique is widely used in transmission of high definition video/audio signals. An HDMI specification (see NPL 1, for example) provides specifications of an HDMI cable and an HDMI connector, so that even when applicable versions of the specification differ, a shape of a connector of Type A, for example, is not changed. Therefore, an old audio-visual (AV) device and a new AV device can be connected by the HDMI cable. Since the HDMI specification provides high compatibility as described above, a cable, a connector, and others that are compliant with the HDMI specification are widely used.
In this description and the claims, in some cases such a connector that is fully compliant with the HDMI specification is described as “a conventional connector”, while a plug and a receptacle that form the conventional connector are described as “a conventional plug” and “a conventional receptacle”, respectively.
In markets, high definition televisions including so-called 4K television sets (the television sets are hereinafter abbreviated as “televisions”) are about to prevail, and higher definition televisions such as 8K televisions emerge as next-generation televisions. With such higher definition television screens, an information amount of video/audio signals to be transmitted also increases. For this reason, the HDMI specification alone can possibly cause an insufficient amount of information that can be transmitted with respect to an amount of information to be transmitted.